Rolling mill



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April 23, 1957 1. PROPERZI 0 ROLLING MILL Filed Feb. 5, 1953 7Sheets-Sheet 7 NVENTORV United States Patent ROLLING MILL IlarioProperzi, Milan, Italy Application February 5, 1953, Serial No. 335,346

2 Claims. (CI. 80-36) The present invention relates generally to rollingmills for metal rods or the like, and more particularly to an improvedrolling mill which comprises a train or series of aligned rolling unitseach contributing progressively to reduce the cross-section of metalstock introduced into the mill.

Rolling mills having a train of rolling units each with a pair ofrolling members are known, but these have the disadvantage in that it isa simple matter for the metal stock being rolled to undergo undesiredrotation from one rolling unit to the other which produces defects inthe rolled product. The rotational tendencies of the stock have beenovercome in the past by the use of three rolling members for eachrolling unit. These rolling members in each unit are placed at angles of120 to each other and exert a concentric pressure over the completesurface of the Wire and, by displacing the rolling members of successiveunits angularly by 60, the rod may be passed through the rolling millfrom one unit to another without being subjected to rotational stressesso that the properties of the ultimate product are substantiallyimproved.

Despite the undoubted advantages of using three rolling members in eachunit with the units arranged in the aforedescribed manner,constructional difficulties have been encountered in providing a rollingmill in which a train of such units is utilized. One difiiculty is thefact that the drive shafts of successive rolling units must be placedalternately above and below the rolling axis due to 'the. fact that therolling members of successive units are displaced 60 with respect to oneanother. Moreover, as a result of the alternate locations of successivedrive. shafts, the rotational drive thereof must be alternately reversedto maintain the rolling in one direction.

Yet another difficulty is the fact that the rate of rotation of therolling members of successive rolling units must be progressivelyincreased because of the elong'ations in the rod due to the reductionofcross-section thereof as it passes from one unit to another.Theoretically the required rate of rotation of the successive rollingunits is a function of the rolled cross-section produced thereby on therolled rod. However, it has been found in practice that strict adherenceto such theoretical rotational speed is not possible. The reason forthis is that the theoretical values are subject to material variationswhen different types of metal stock are rolled and for differenttemperature conditions. Consequently, for satisfactory operation it isnecessary that the rolling mill be capable of simple adjustment toaccommodate different metals and for different temperature conditions.Unless such an adjustment is provided, the rolled rod undergoesexcessive tensional and compressionat strains which result either infracture or in unsatisfactory operation of the mill.

, It is an object of the present invention to provide an improvedrolling mill in which the difiiculties and 2,789,450 Patented Apr. 23,1957 "ice problems encountered in the art are overcome for all practicalpurposes.

7 A further object of the invention is to provide such an improvedrolling mill which includes a series of rolling units in which therolling members of such units are driven in a simple, efiicient andhighly improved manner.

Yet another object of the invention is to provide such an improvedrolling mill including a series of rolling units in which such units arereadily adjustable so that the mill may accommodate difierent metals andoperate under different temperature conditions, thereby increasing theflexibility of the mechanism.

Yet another object of the invention is to provide such an improvedrolling mill which includes a series of individual rolling units whichare so constructed and driven that the overall dimensions of the rollingmill are reduced to a practical minimum.

A still further object of the invention is to provide such an improvedrolling mill which may be readily accommodated to produce rolled metalrod of a wide variety of diameters.

A feature of the invention is the provision of an improved rolling millcomprising a train of rolling units with drive shafts positionedalternately above and below the rolling axis, in which only one of agroup of such units is directly driven and transmites rotational motionto other units in the group in the proper direction and at appropriatedifferent speeds for each unit, by means of a simple replaceable pinionand gear arrangement. This provides an extremely simple, rugged andaccessible assembly, and also allows the various rolling units to beplaced in close proximity one with the other to decrease the overalldimensions of the rolling mill.

Another feature of the invention is the provision of an improved rollingmill which is constructed so that the individual rolling unitsconstituting the mill may be expeditiously excluded from the train forcleaning purposes, or for enabling the metal stock to be withdrawn fromthe mill at any intermediate point when it is required to produce a rodof a cross-section which is larger than would bethe case were it totraverse the whole train.

Another feature of the invention is the provision of an improved rollingmill in which the rolling cross-section in each rolling unit may beconveniently adjusted to'accommodate different metals having difierentmoduli of elasticity or to compensate for different temperatureconditions.

The above and other features of the invention which are believed to benew are set forth with particularity in the appended claims. Theinvention itself, however, together with further objects and advantagesthereof may best be understood by reference to the accompanying drawingin which:

Fig. 1 illustrates one type of rolling unit for incorporation into therolling mill of the invention having its drive shaft positioned belowthe rolling axis,

Fig. 2 is a longitudinal section through the rolling unit illustrated inFig. 1,

Fig. 3 is a cross-sectional view of a second type of rolling unit forincorporation into the rolling mill having its drive shaft located abovethe rolling axis,

Figs. 4 and 5 are detailed views of a portion of the rolling unit ofFig. 3.

- Fig. 6 is a front elevation of the complete rolling mill constructedin accordance with the invention and arranged on a common base,

- Fig. 7 is a plan view of the rolling mill shown in Fig. 6, Fig. 8 is arear elevational view of the driving means for the rolling mill of Figs.6 and 7,

Fig. 9 is a cross-sectional view taken along the line 9--9'of Fig. 8, i

the transmission mechanism for the various rotary spindles 35-37 and theengagement of these spindles with the drive shafts of rolling units22-34, is shown in Fig. 7. As previously pointed out, the first group ofspindles is driven from the main spindle 39 to which the toothed crown62 and gear wheel 65 are rigidly connected, whereas the second group isdriven from the main spindle 45 which has a similar toothed crown 64 andgear wheel 66 affixed thereto. The transmission mechanism for one groupof spindles is shown in perspective in Fig. 10, it being understood thata similar arrangement is used for the other group. As previously noted,it is necessary that the various spindles of each group be rotated atdifierent speeds, and also that successive spindles be rotated inalternate directions, this being achieved by the transmission mechanismof Fig. 10.

As previously pointed out, the main spindle 45 derives rotary motionfrom the main driving means directly through the toothed crown 64rigidly connected thereto; Gear 66 is also rigidly connected to the mainspindle and engages a gear 67, the latter being rotatably mounted onshaft 69 and rigidly secured to 'a further gear 68 of smaller diameter.Gear 68 meshes with a rotatably mounted reversing gear 70, the latterengaging a gear 71 fixed to spindle 44. In this manner, rotation at areduced speed is imparted to spindle 44, which is positioned above therolling axis, in a direction opposite to the rotation of spindle 45below the rolling axis. It is to be noted that gears 66, 70 and 71 areof equal diameter and have the same number of teeth, the reduction inrotary speed of spindle 44 with respect to thatof spindle 45 beingdetermined solely by the ratio of the diameters and the number of teethof gears 67 and 68. This simple arrangement provides for high powertransmission in a relatively small space.

Gear 70, in turn, transmits rotary motion to gear 75 on spindle 43through a pair of gears 72, 73 rotatably mounted on shaft 74, the largerdiameter gear 72 engaging gear 70 and the smaller diameter gear 73meshing with gear 75. In this manner, spindle 43 is rotated in theopposite direction to spindle 44 and with a decreased speed. In asimilar fashion, rotation is transmitted from gear 75 to spindle 42 sothat the latter spindle rotates in the opposite direction to that ofspindle 43 and with a decreased speed relative thereto.

At the left-hand side of Fig. 10, gear 66 engages a gear 76 which,together with a gear 77 of larger diameter rigidly connected thereto, isrotatably mounted on a shaft 78. Gear 77 engages a rotatably mountedrevers' ing gear 79 which, in turn, meshes with a gear 80 secured tospindle 46. In this manner, spindle 46 is rotated in a directionopposite to the rotation of spindle 45 and with increased speed relativethereto. Gear 79, likewise, drives a gear 81 rigidly secured to spindle47 through a pair of atiixed rotatable gears 82 and 83, gear 83 beingsmaller than gear 82 so that spindle 47 rotates in a direction oppositeto the rotation of spindle 46 and at an increased speed.

With the transmission described above, it can *be seen that spindles4247 are rotated at progressively greater speeds and in alternatelyopposite directions. In the gear train, not only are the gear wheels 66,70, 71, 75, 79, 80, 81, etc., of the same diameter and have the samenumber of teeth; but all the gear pairs 67/68, 72/73, 76/77, 82/83,etc., are also identical and are merely inserted and alternatelyreversed in the transmission mechanism to the right and to the left ofthe main spindle 45, in accordance with the speed increase or speedreduction required. This arrangement not only greatly simplifies thetransmission mechanism but provides for rapid and convenientinterchanging of the elements for replacement purposes.

Since the transmission ratio of the various gears of Figs. 7 and isinvariable, means is provided in the rolling mill for adjusting thecross-sectional area of the rolling pass defined by each rolling unit sothat precise adjustment for difierent types of metal stock and forvarying temperature conditions can be made. This adjustment isillustrated in Figs. 3, 4 and 5. As shown in these figures, drive shaft17 is rotatably mounted in bearings in a bracket 84, the bracket beingsecured by bolts 85 and 86 to the sides 87 and 88 of the casing of therolling unit. In this manner, the drive shaft 17 is rigidly held forrotation about a horizontal axis and is immovable with respect to thataxis. Rolls 19 and 20, on the other hand, are rotatably mounted onshafts 89 and 90, the shafts being respectively supported in bearings inbrackets 91 and 92 which, in turn, are secured to the sides 87 and 88 ofthe rolling unit by bolts 93 and 94 respectively passing therethrough.

As more clearly shown in Fig. 5, bolt 94 is mounted in the sides 87 and88 of the roller unit so that it can be readily shifted'towards or awayfrom the rolling axis by means of screws 95, 96 and 97, 98 threaded intothese sides. Adjustment of screws 95, 96 and 97, 98 moves bracket 91and, therefore, roll 19 towards or away from the rolling center by asmall amount to control the crosssectional area of the rolling passdefined by the rolling members. These minor displacements of bracket 91are kept within the engagement 99 between previously described bevelpinions 0n drive shaft 17 and shaft 89. As shown in Fig. 4, bracket 91is disposed in a guide 101 in side 87 and a similar guide in side 88 toinsure that the displacement takes place parallel to the originalposition so that the shape of the rolling pass remains unchanged forvariation in its cross-sectional area. It is desirable that a similarlateral shifting adjustment may be provided for bolt 93 of bracket 92 sothat the same configuration can be maintained for the rolling pass asits dimensions are altered. In this manner, although the rolling speedof each rolling unit is invariable, the crosssectional area of eachrolling pass may be adjusted to accommodate a wide variety of metals anddifierent temperature conditions.

As previously pointed out, the rolling mill of the present inventionalso has the feature in that individual rolling units may be excludedfrom the rolling train for cleaning purposes or when the rollingrequirements dictate a lesser number of rolling units. This feature ismore clearly shown in Fig. 11 and, as illustrated in this figure, eachrolling unit is mounted on base 112 by means of a threaded rod 108 whichis secured to the base at its lefthand end. Rod 108 has a sleeve 106coaxial therewith, the latter having internal threads engaging thethreads on the rod and the sleeve being secured to a rolling unit, heredesignated as 110. Sleeve 106 has a squared end 107 which may be turnedby means of a key applied thereto, and rotation of sleeve 106 causes theentire rolling unit to move to the right of the drawing with its splineddrive shaft 4 disengaging its corresponding rotary spindle 114, thelatter being rotatably mounted on the upstanding bracket portion 111 and113 of the base in the manner previously described and having aninternally toothed socket. In this manner, by rotating sleeve 106, therolling unit may be moved along sliding path 109 away from the rollingaxis of the rolling mill and into an inoperative position. When it isdesired again to place rolling unit 110 into an operative position, itis merely necessary to rotate sleeve 106 in the opposite direction andretract the unit.

The present invention provides, therefore, an improved rolling millwhich is constructed to provide a relatively large number of rollingpasses in a relatively small space and which incorporates a uniquedriving arrangement in which the rolling passes are arranged in drivinggroups so that the relatively large number of such units may be drivenall with high power. It is of course to be understood, that when anadditional number of passes is required, further groups may be provided.The invention also provides a rolling mill in which the cross-sectionaliarjeassofrithesvarioussrolling,;passes-;may:be adjusted: for differentconditions inaa simple and. convenientmanner,

succession ofirollingaunits:supported on .said.base struc- ..ture,.eachincluding three'rollingm'embers angularlyspaced with respect to oneanother 'saidrollingzmerrrbersof-successivezoneszof said .units beingangularly-displaced :from ronernnit to ithenextiand defining-ta seriesof rolling passes spacedtalongarolling axis,'-.said rollingunitsbeingmoveblei horizontally-on said ibasel along-sanl axis.transverse ion-said: rollingeaxis, alfirstrgroupr-of:drivesh-afts forafirstr. group :of' :said' rolling ."units respectively-:. extendingalong horizontal axes :perpen'dicular :totsaidrrolling axis zandaabove zsaid' rolling axis, .a second ..group of drive :shafts for :asee'nodigroup rofwsaidrolling .units'irespecti-vely zextendingalonghorizontal axes perpendicular .to

saidrrolling :axis and; below rsaid rolling axis, said-"shaftsLoft-said. rolling units being positionedinalternationialongsaidszrollingz axis. and..said drivessh'afts :of said first and second.groups ibeingrotatable .in opposite directionsto drive. :said rollingunits, with. said shaft having. splined extremities, a1.first .groupziofspindleszrotatably mounted nnssaidtbasefin respective alignmentwith saiddrive shafts :ohonemf;saidzgroups,.a second-group of spindles interposedflwith'ithe spindles ofsaid first .group in respective alignment.Withsaid :drive shafts :of the :other' of said groups;rsaidvspindieshaving rsplined socket 'portion for engagingtta correspondingxone ofsaid splined shafts, a adnivingmiechanism for imparting rotationalmotion to one of said spindles, a first series of 'gearwheels -respec--tivelyeaflixedto said spindles-of said first :group, a secondseries'sofsgear wheels arespectively afiixed to said' spind1cst1of;said:second.1 group, a-series of reversing gear :wlreelsrotatablyniounted on-said base .in respective em gagemenbwithsaiti'igearWheels soft said. first series, taz'series of ilike pairszofs coaxialmutually: affixed; gear Wheels 10f unequal A diameters r rotatably."monnted on :said base respectively interposed :between said reversing-gear Wheels and said .-,-gear1-wheels: .of said second series, with?one gear wheel of each-of said pairs engaging a corresponding'one ofsaid reversingsgear wheels and -with-.the other v gear whee1 of. each.of 'said pairs engaging .a corresponding one oftsaidggear' wheels of;said second series, a first elongated threaded member-.monnted.-.onsaidbase adjacent each said movable rolling. unitzandextending acrosssaid'rolling axis and a second elongatedthreaded member mountedonsaidnr'olling uriitincoaxial and'threaded relation with .said.firstt-threaded member, so -:that rotation -.of one .said :threadedmember-s imparts individual. horizontal movement to said movable.rolling unit transverse .to said rolling axis.:between .an operative.position .inwhich said splined extremity of :the drive shaft-thereofengages-said socket:andaninoperative position. in which the. drive shaftof .said movable rollingiiintisdisengaged from said socketandsaidmovableunit .is'displaced entirely frorn said r011- .ing axis.

.2. .A.machine--as.defined inclaim 1 wherein saidrollingmembers.o..said..r0lling units aremountedon shafts, meansoperativelyconnected-to atleast one-of said shafts to adjusttherbllingmember toand away from said rollingaxis.

. References" Cited in thei-ileofthis patent UNITED STATES- PATENTS287,008 Daniels Oct. 23, 1883 332,572 Tucker "Dec. 15, 1885 351,841Lenox "Nov. 2, 1886 3883389 Bansen Aug.'28, 1888 433,286 Hanks July 29,1890 439.;878 Kellogg -Nov. 4, 1890 455,621 Hicks July 7, 1891 518,608Kent Apr. 24, 1894 616,092 Eynon Dec. 20, 1898 1,930,698 "Stie'fel Oct.17, 1933 I 2;003,551 -Nygren June 4, 1935 2,053,694 'Buchels Sept. 8,1936

